The present invention is directed to a mechanically operated jacks and, more particularly, an improvement for a jack in which the extreme positions of its piston are automatically locked and can be unlocked manually or automatically.
Traditionally, there are many different types of jacks, for example, hydraulic jacks, pneumatic jacks, and others, which are used for various applications. These jacks frequently encounter problems associated with their particular utilization, such as, when the operating energy of the jack fails, for example, a pressure drop in a pneumatic jack, so that the piston/piston rod unit becomes motionless. Likewise, in certain jacks, a drop in gas pressure automatically locks the piston in position and the piston cannot be unlocked or moved until the necessary operating energy is reestablished.
Further, the different devices in existence which allow locking of the piston and its rod usually require additional pieces or meticulous machining of some of its component parts, making their manufacture delicate, long, and onerous.
Thus, it is the object of the present invention to resolve the aforementioned problems with the aid of simple means, which are reliable and less onerous. The present invention contemplates a new and improved jack which can be unlocked in its extreme position and which can be unlocked easily either manually or automatically in case of a breakdown.